Various turbine-generator designs have been utilized to produce electric power for many years and are well documented. A typical turbine generator system is an electrical generator device that converts kinetic energy derived from a fluid flowing under pressure to electrical energy usually using electromagnetic induction. Though there are a multitude of different designs that describe various types of hydroelectric turbine systems that serve different applications, they all share a single objective. That is, they seek to produce as much electric energy as possible utilizing as much available hydraulic flow and pressure as possible. Maximum efficiency is characterized, in these designs, by achieving high levels of electrical production using all available fluid flow and particularly pressure from a supply source. None, if any, considers the condition of the fluid material once it has left the surface of the final blade or impeller vane that serves to drive a generator shaft.
A traditional turbine-generator system consists of a turbine impeller, impeller housing, and a generator or alternator device which are coupled via a shaft. The turbine is used to convert momentum from a fluid stream into rotary motion. The shaft transmits the motion to the generator rotor, which typically contains permanent magnets or coil windings around each of its poles. Power is generated by flow under pressure that comes into contact with an impeller or a multiple blade type device that turns a common shaft.
There are different types of impeller designs and are generally considered reaction, cross flow or impulse types. They develop kinetic energy by the drive force supplied by a concentrated stream or jet of fluid which is deflected off cups or paddles tangentially or axially across an impeller such as in a Pelton, Turgo, Banki, Kaplan or Francis turbine designs. The water's potential energy is converted to kinetic energy with a nozzle or restrictive orifice in some cases. The high speed water jet is then directed onto the turbine blades which deflect or reverse the flow such as is characteristic of the popular Turgo turbine design. The Francis turbine is also a common design used in many large applications such as dams and flowing rivers where piping is used to convey water down flumes to develop head pressure that drives this reaction type turbine, which means that the working fluid changes pressure as it moves through the turbine, surrendering its energy. A casement or housing is needed to contain the water source or intake flow and is called an inlet scroll. The impeller is located between the high pressure fluid supply source and the low pressure water exit located just after the impeller.
The Francis turbine's volute or inlet scroll is spiral shaped. Guide vanes direct the water tangentially to the runner. This radial flow acts on the runner vanes, causing the runner to spin. The guide vanes or wicket gate may be adjustable to allow efficient turbine operation for a range of water flow conditions. The impeller is an inward flow design and moves the fluid through the runner as its spinning radius decreases, further acting on the secondary runner blades or vanes.
Virtually, all hydroelectric turbine generator designs share a common objective of producing as much electric energy as possible and prefer maximum flow under high pressure to achieve that goal. Efficient designs are built upon the premise of extracting as much energy as possible from the fluid flow under pressure driving the system and are not, typically, concerned with the state of the flow once it has been discharged from the impeller. That is, the primary objective is energy production and not sustained downstream pressure. Such designs achieve higher flow velocity by increasing head pressure using several means and equate efficiency to the design if it uses all available pressure to produce electricity. A common turbine design modifies inlet flow by attempting to concentrate it prior to its contact with the impeller. This is accomplished by the use of nozzles or channeling flow down into a smaller orifice, chamber or pipe size diameter like a flute type structure to increase the flows pressure right before it contacts the turbine. Such restriction increases flow velocity or speed across the impeller's veins or blades and turns the generator faster to produce more power, but subsequently sacrifices downstream pressure in the process.
However, there are numerous other uses or applications that would benefit substantially from hydroelectric turbine power if it could be utilized, but can not at this time because of the restrictive nature or pressure differential characteristics. A product has not been developed, to this point that specifically addresses the needs of such applications or markets where electricity is use to power various electronic devices.
Fluid flow conveyance systems like piped irrigation or large volume water, oil or gas transfer and especially ones that are remotely located or difficult to access with conventional power are best managed using processor driven control systems that incorporate sensor input and communication capability. Applicable electronic control technologies that enable various levels of monitoring and management control of remotely located pipe lines require electricity. Such systems are usually supplied by metered utility power, wind or solar power which can be difficult to impossible or impractical to implement. Therefore, furnishing power to electronic control and/or communication systems, lighting etc. using energy derived from the same pipe lines the system is managing, or in close proximity to, would provide an ideal power alternative.
Solar and wind electrical generation are good renewable energy alternative sources but have several disadvantages. From an aesthetic stand point they are not attractive for urban and suburban use and can be susceptible to vandalism because of the high profile installation requirements of both systems. Both require that they be placed sufficiently high above grade level in order to effectively capture and produce energy, which make them a good target for vandals. Furthermore, in remote locations like rural environments, they are even more susceptible to theft and vandalism, again because of their high profile nature necessary to produce power. Solar and wind generating systems can be very expensive to purchase and do not guaranty a regular supply of energy. They are dependant upon favorable weather conditions, which can present enormous problems to mission critical systems that might depend on them for power.
What is needed then is a hydroelectric turbine generator system that is designed to extract a particular amount of energy from a fluid flowing under pressure yet is able to sustain most of or a majority of the inlet pressure downstream of the turbine device. Such a system would allow the production of electric power to implement important electronic components or other electrical equipment and still permit the continued operation of the fluid transfer system by sustaining its required operating pressure.
It is therefore, the purpose of this invention to provide a method that addresses the need for generating electric power using an inline turbine-generator system, which generally consists of a reaction type axial impeller, turbine housing and an electric generator device. This invention's method provides a hydroelectric turbine system that is able to generate a particular amount of electric power by converting energy from fluid flowing under pressure through a pipe, that subsequently drives the impeller connected to a shaft that turns a generator device that produces electricity, and systematically sustains a majority of the upstream inlet pressure downstream of the turbine housing's discharge end. Furthermore, and critical to this invention's method, is the expeditious manner in which fluid is conveyed through the system by maintaining as much flow velocity as possible.
Since the design objective of this invention is to produce enough energy to power, for example a control system, solenoid valves and/or an electrical storage means like batteries or capacitors that supply the system when generated power is not available. However, when supplying a charge to batteries, more is always better to assure the maximum amount is saved and stored. Creating a sufficient amount of voltage and current, or even more, does not require significant pressure or pressure loss to the hydraulic system due to the efficiency of the inventions turbine design. This turbine design can produce over ten amperes of power depending upon the generator or alternator device used in conjunction with the system and the impeller vane height and length, and is enough to supply a charge to a battery and an electronic system's requirement. Surplus hydraulic pressure is subsequently used so that very little, if any, is wasted.